Major ion toxicity in effluents: A review with permitting recommendations

Abstract

Abstract-Effluent toxicity testing methods have been well defined, but for the most part, these methods do not attempt to segregate the effects of active ionic concentrations and ion imbalances upon test and species performances. The role of various total dissolved solids in effluents on regulatory compliance has emerged during the last few years and has caused confusion in technical assessment and in permitting and compliance issues. This paper assesses the issue of ionic strength and ion imbalance, provides a brief summary of applicable data, presents several case studies demonstrating successful tools to address toxicity resulting from salinity and ion imbalance, and provides recommendations for regulatory and compliance options to manage discharges with salinity/ion imbalance issues. Effluent toxicity resulting from inorganic ion imbalance and the ion concentration of the effluent is pervasive in permitted discharge from many industrial process and municipal discharges where process streams are concentrated, adjusted, or modified. This paper discusses procedures that use weight-of-evidence approaches to identify ion imbalance toxicity, including direct measurement, predictive toxicity models for freshwater, exchange resins, mock effluents, and ion imbalance toxicity with tolerant/ susceptible text species. Cost-effective waste treatment control options for a facility whose effluent is toxic because of total dissolved solids (TDS) or because of specific ion(s) are scarce at best. Depending on the discharge situation, TDS toxicity may not be viewed with the same level of concern as other, more traditional, toxicants. These discharge situations often do not require the conservative safety factors required by other toxicants. Selection of the alternative regulatory solutions discussed in this paper may be beneficial, especially because they do not require potentially expensive or high-energy-using treatment options that may be ineffective control options. The information presented is intended to provide a better understanding of the role of ion imbalance in aquatic toxicity testing and to provide various recommendations that should be considered in addressing these issues.

Recirculating – Reducing and Alkalinity Producing System (Reraps) for the Treatment of Acidic Coal Pile Runoff

“…The total recoverable analytical procedure for metals may be measuring aluminum associated with the suspended clay particles from the ReRAPS liner and therefore could be a biased estimate of the suspended Al hydroxide. The major ion or salinity effect should also be evaluated if complete toxicity removal of acidic runoff is required (Goodfellow 2000).…”

Predicting release and aquatic effects of total dissolved solids from Appalachian USA coal mines

“…… This impairs the use of the streams and ultimately leads to listing of these streams as 'impaired water bodies' in EPA's water quality reports …'' (Pomponio 2009). Several recent studies (Chapman et al 2000;Goodfellow et al 2009;Pond et al 2008;Timpano et al 2010) have addressed the issue of TDS as a major stressor upon receiving streams in mined watersheds and are discussed in more detail later in this paper. More recent EPA guidance (issued in 2011; subsequently withdrawn) was based on the belief that mine discharges with EC levels\300 ls/cm generally will not cause significant degradation of the aquatic ecosystem while instream conductivity levels [500 ls/cm are likely to be associated with significant adverse impacts on the aquatic ecosystem.…”

Lake Water Monitoring Data Assessment by Multivariate Statistics

“…The choice of quality parameters is normally standardized and described in various instructions and directives for individual countries or unions like EU [1][2][3][4]. Recently, a very specific attention requires a different type of water quality parameter called "toxicity" ("ecotoxicity") [5][6][7]. It is also important to note that lake waters are important element of the aquatic ecosystems.…”